WHAT: When the START I arms-control treaty expires Saturday, the U.S. will lose its full-time, on-site access to the factory where all Russian intercontinental ballistic missiles are built. The Obama administration insists it was “stuck” with an agreement reached by the Bush administration but not made public. Former Bush arms-control officials dispute this claim.

WHY IT’S A BAD IDEA: The U.S. stopped making new long-range missiles, so Russia voluntarily left its reciprocal Utah inspection site eight years ago. But Russia built dozens of missiles since the monitoring started 15 years ago. START banned certain types of missiles, which Americans verified by inspecting every missile leaving the factory.

WHAT’S BEING DONE: Moscow and Washington, D.C., are drafting a new arms-control treaty to replace START, with a goal of reducing strategic nuclear warheads to no more than 1,675 within seven years. Interim verification measures to replace America’s missile inspection site also are being negotiated.